Constraint satisfaction in a resource allocation problem optimized using evolutionary algorithms

I am working on a allocation problem where a resource R needs to be allocated to n users each with demand . The problem has two objectives: objective 1 - maximize user utility given by and objective 2 - minimize , a loss funcstion associated with a user for providing his the resource. Here is the allocation to user and and are constants. The problem has two constraints (allocaton is ≤ demand) and (sum of all allocations equals total available resource). Overall, I need to maximize aggregate system utility () and minimize aggregate loss (). I am using evolutionary algorithm for this problem. But, after the evolution is complete, the algorithm leaves unallocated resoruce while there is still unmet user demand. I am curious if it is a expected outcome or it is due to some algorithmic or implementation flaw. I would appreciate any guidace.